Comparison

Partial Sums Addition vs Back in Time

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Partial Sums Addition

This app teaches and reinforces the partial sums addition method. It offers an interactive interface with customizable settings, allowing users to solve random or custom addition problems with varying numbers of digits and addends. The app provides immediate feedback and aligns numbers automatically for focused learning.

Highlights
  • Partial sums addition method teaching
  • Interactive and customizable interface
  • Random and custom addition problems
  • Adjustable number of digits and addends
  • Automatic number alignment
  • Immediate feedback on answers
  • Color and animation speed customization
Features
Read full description

Partial Sums Addition helps students learn and practice the partial sums addition method step by step. The app gives students a visual way to add numbers by working with each place value separately. The partial sums are then combined to find the final answer. Students can solve randomly generated problems or enter their own addition problems. The number of digits can be adjusted for different skill levels. The Partial Sums Method: In the partial sums method, each place value is added separately from left to right. For example, in 764 + 340, the partial sums are 1000, 100, and 4. These are then added together to get the final answer: 1104. Wired.com: “Esa Helttula’s apps are all fantastic for math learning and practice, and aren’t cluttered with mini-games, incentives, or annoying music.” Teacher endorsement: “The math apps by Esa Helttula allow students to practice and reinforce the specific computation strategies taught in class, with as much or as little scaffolding as necessary. They also provide individualized feedback to each student, with an immediacy that is not always possible through pencil and paper practice.” — R. Zeni, Ecole Sandy Hill Elementary, Abbotsford, BC, Canada Easy to Use: The numbers are aligned automatically so students can focus on solving each column. After the student solves the operation for each column, the correct answer moves into the right place. If the student presses the wrong button, the answer appears above the keyboard but does not move. Features: - Step-by-step partial sums addition practice - Add 2 or 3 numbers - Each number can have 2–3 digits - Randomly generated or manually entered problems - Current operation for each column can be hidden - Operands of the current operation can be highlighted - Customizable interface colors - Adjustable animation speed - Custom interfaces for iPhone and iPad Other iDevBooks Math Apps: Other iDevBooks math apps include Column Addition, Long Multiplication, Long Division, Column Subtraction, Visual Multiplication Table, Partial Differences Subtraction, Partial Products Multiplication, Partial Quotients Division, Decimal Rounding, and more. Feedback: New ideas to make this app better are welcome. Please visit idevbooks.com to give feedback. Privacy: This app has no ads, no in-app purchases, and does not transmit user data during operation. The app also does not contain links to other apps or to the web.

About

Back in Time

Explore the history of the Universe, Earth, Life, and Civilization through an immersive, interactive journey. This app uses custom animations, timelines, and interesting facts to bring historical events to life. It's designed to help users understand the connections between events and see the bigger picture.

Highlights
  • Interactive timeline of events
  • Custom animations and videos
  • Over 350 remarkable images
  • Little-known interesting facts
  • Offline access
  • Multilingual support
Features
Read full description

• "The coolest history textbook you’ll find on the iPad" - The New York Times • Winner of the WSA Mobile Award • Top1 iPad Book in US, UK, FR, ES, China… and 34 more Countries • Featured by The New York Times (Top10 iPad Apps of the year) • Featured by the American Photo Magazine (Top 10 Photo eBooks of the year) For iPhone/iPod touch download - Back in Time for iPhone Back in Time will take you on a stunning exploration of the history of our Universe, Earth, Life and Civilization. A journey through time where each event is documented with social and historical context, several images, an illustrative timeline and little-known interesting facts. Custom made animations bring those events to life, creating an interesting, immersive learning experience. An imaginary clock will guide you through this quest, proposing a simple analogy: the entire Universe started 24 hours ago. The Big Bang, the source of time and space, is the first event in our journey – the clock reads 0:00 hours. Today, 13.7 billion years later, the clock reads midnight. In between is a sequence of key events that has brought us to where we are today. Explore them, place them in perspective, see how they relate and understand the connections. We invite you to take a step back and see the whole picture. :::: REVIEWS :::: “...a beautifully executed lesson on the history of the universe and the evolution of life on earth. Great for high school students or parents who’d like to tutor younger children and enjoy a first-rate experience of their own...” - Bob Tedeschi, The New York Times “The iPad could use more apps like this one.” - The Daily “...the best iPad apps are those that combine coffee table-styled books with the fluid nature of the iPad’s interface. Back in Time is just that, it’s the story of the entire history of our universe made interactive on the iPad.” - Casey Chan, Gizmodo (App of the Day) “Back in Time is utterly gorgeous in its presentation. (...) The app is so easy to navigate that it is a delight to explore. Landka could scarcely have done a better job in putting everything together.” - Gwen Phua, Appmodo :::: FEATURES :::: Designed for iPad; 47 chapters; Over 350 remarkable images; 60+ amazing animations and videos; 40+ illustrated timelines; More than 200 little-known interesting facts; Music by the composer Rodrigo Leão; Developed in 7 different languages (English, Spanish, German, French, Portuguese, Japanese and Chinese); No internet connection required.

Screenshots

Partial Sums Addition4 screens

Verdict

The call

The clearest difference is review sentiment: Back in Time at 84% against Partial Sums Addition's 50%. Back in Time also leads on ratings volume (25 vs 2). Partial Sums Addition's advantage is rating (5.0 vs 4.6) and price ($3.99 vs $7.99). On update cadence, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Partial Sums Addition costs $3.99 and Back in Time $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Partial Sums Addition holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Back in Time has 25 ratings behind it against 2, so its average is the more settled of the two. Written reviews complicate that: 50% of Partial Sums Addition's written reviews are positive against 84% of Back in Time's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Partial Sums Addition ships an update every 9 months, Back in Time every 7 months. The most recent releases landed on October 12, 2026 and October 7, 2026 respectively.

Scorecard4 real differences · 6 level
Partial Sums Addition versus Back in Time: the parameters behind the verdict, then further details
ParameterPartial Sums AdditionBack in Time
Price$3.99 — better$7.99
Rating5.0 (2 ratings) — better4.6 (25 ratings)
Positive reviews50.0% of reviews83.7% of reviews — better
Number of ratings225 — better
Update frequencyEvery 9 monthsEvery 7 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad — betteriPad
Requires iOS17.616.0 — better
Further details — not scored
Size1 MB836 MB
Age rating4+4+
DeveloperEsa HelttulaLandka

Customer experience

Partial Sums Addition

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

Back in Time

All ratings25 ratings
Positive92.0%
Neutral4.0%
Negative4.0%
Written reviews43 reviews
Positive83.7%
Neutral7.0%
Negative9.3%

In-app purchases

None

Partial Sums Addition

No in-app purchases

None

Back in Time

No in-app purchases

Questions

Is Partial Sums Addition free?
Partial Sums Addition costs $3.99, with no in-app purchases.
Is Back in Time free?
Back in Time costs $7.99, with no in-app purchases.
Which has better reviews, Partial Sums Addition or Back in Time?
Partial Sums Addition is rated higher. Partial Sums Addition averages 5.0 out of 5 from 2 ratings, while Back in Time averages 4.6 from 25 ratings.
Do Partial Sums Addition or Back in Time have ads?
Neither Partial Sums Addition nor Back in Time shows ads.
Which is updated more often, Partial Sums Addition or Back in Time?
Partial Sums Addition ships an update every 9 months, and Back in Time every 7 months. Most recently, Partial Sums Addition was updated on October 12, 2026 and Back in Time on October 7, 2026.

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